Hartshorne’s metaphysical position is indeterministic, psychicalist, and theistic. The most pervasive fact of experience, according to Hartshorne, is creativity, the becoming of novel actualities. Whitehead said in Process and Reality that the “many become one and are increased by one.” Hartshorne expresses the same idea by saying that “to be is to create.” The extent of novelty is a matter of degree, ranging from a minimum in the nearly exact repetition of pattern at the inorganic level to the maximum in artistic creation at the human level. Of course, experience is also marked by law-like regularities, and science is largely occupied in discovering “laws of nature.” Hartshorne insists, however, that the determinist’s view that sufficient causal conditions can, in principle, be found for every event is not warranted by experience. The regularities perceived are never so exact as to eliminate novelty. Causes provide the necessary, not the sufficient, conditions for the emergence of new actual entities. When causes severely limit the possible range of effects, one finds the stability of order that is reflected in the laws of nature.
Indeterminism can, thus, account for nature’s regularities, whereas determinism cannot account for its novelty. This point is often missed, because indeterminism is mistakenly identified with the view that events are never causally conditioned. Hartshorne argues that the becoming of an actual entity is always causally conditioned, but that causes never guarantee every detail of their effects. Therefore, an effect is always “more than” its causes; the surplus is the measure of novelty in the world. Perfect knowledge would allow one to deduce causes from an effect, but no amount of knowledge would allow one to deduce an effect from its causes. It is not simply a limitation of knowledge that prevents one from predicting a poet’s next poem: such a prediction would amount to composing the poem oneself.